Prion-related diseases have been found to be transmissible from one human to another. This was discovered from studies of a formerly cannibalistic population in New Guinea who honored their dead by using ritual cannibalistic rites. Children typically ate the brains of their deceased parents during these rituals. Many of them contracted a disease similar to CJD called "kuru" (which, in their native tongue, means shivering or trembling).17 The disease sometimes took up to 30 years to develop. Young children who engaged in these cannibalistic practices seemed to develop the illness sooner than their older siblings or peers who also consumed infected brains.18
Other examples of human-to-human transmission of these devastating illnesses exist. Before synthetic human growth hormone was available, individuals who were deficient in this important compound often received it from pituitary glands removed from human cadavers. There are reports of CJD being transmitted by this process. Other body products from human cadavers have also been linked to CJD transmission. These include eye (corneal) tissue and dura mater (a natural brain covering used during some brain surgeries).19 Medical devices have transmitted CJD, including contaminated electrodes that are used to measure brain waves in a special EEG test.20
One fascinating study emphasized the tenacity of these disease-bearing prions.21 Electrodes were used to probe the brain of a demented patient who turned out to have CJD. The disease was inadvertently transmitted to two other patients when the same electrodes were used on them. Following their last use in humans, over two years passed. During that time the electrodes were cleaned three times and repeatedly sterilized with ethanol and formaldehyde vapor. After this long interval, the electrodes were reimplanted in a chimpanzee's brain. Within 18 months the chimp had come down with CJD. The authors concluded: "This finding serves to re-emphasize the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them."
Ten Young Infected Britons Awakened Public Health Officials
It was Creutzfeldt-Jakob statistics that really got the medical community's attention in March 1996. By that time 10 young Britons and several farmers had become victims of this devastating illness, as described in Figure 6: Britons Died of Creutzfeldt-Jacob Disease.
The fact that the disease affected a group of individuals whose average age at death was less than 28 (and who were all younger than 42 when diagnosed) 22 was extremely unusual. As we have already pointed out, CJD is typically a disease of older adults. Furthermore, all 10 of these individuals had similar symptoms--but those symptoms were different from those that usually accompanied CJD. For example, instead of causing death within 6 months, this apparent CJD variant lingered for up to 23 months. The brain wave patterns of the diseased individuals differed from the usual CJD patient, as did the type of mental impairment they suffered as the disease progressed.23
These unusual disease features prompted a group of leading British scientists to raise the concern that a new variant of CJD had emerged. They felt the most likely source of this variant was BSE,24 meaning that this form of CJD was transmitted from the meat of cows infected with BSE. Further thickening the plot was the occurrence of a worrisome cluster of CJD-infected British dairy farmers. Four such farmers had died with CJD in the past three years. Statisticians said that such a cluster would be very unlikely to occur simply by chance.25
According to the microbiologist Dr. Jeffrey Almond, a researcher and spokesman (at the Conference on Emerging Infections at Harvard University) for the British government's BSE advisory committee, as of June 1997 there had been 19 confirmed cases of this new CJD causing death, one of which occurred each in France and Italy.
